JPH0399862A - Printing apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a printing device that forms an image using an electrophotographic process such as an LED printer or an LCD printer.

[Conventional technology]

Printing devices that form images using an electrophotographic process are
A photoreceptor is irradiated with emitted light or transmitted light based on image data from a print head such as an LED head or an LCD head, and the electrostatic latent image formed on the photoreceptor is developed into a toner image by a developer, and then transferred to a transfer device. This is a device that prints on paper by transferring it onto the paper. The configuration of such a printing device basically includes a printing section provided with the above print head, etc., and a so-called image forming section provided with the above photoreceptor, developer, transfer device, etc.

However, print heads such as LEDs and LCDs have different arrangement densities depending on their constituent elements. Therefore, the electrostatic latent image formed on the photoconductor by the light emitted from each print head or the light transmitted through the print head is transferred to the paper by the image forming section. The image density (resolution) of the image printed on the image differs depending on the print head. This means that if different print heads are used, the speed at which light is written onto the photoreceptor will change, and sequence processes such as the rotational speed of the photoreceptor and the feeding speed of the paper must also be changed.

For this reason, conventionally, the control section that controls the image forming section is equipped with a ROM that stores sequence programs corresponding to the print head used, or a de-knob switch is used to select and set the program corresponding to the print head used. We are making adjustments.

[Problems with conventional technology]

However, the RO that supports printing and printing as mentioned above
Using M increases the cost of the entire printing device due to the cost of creating the ROM.

Additionally, adjusting the de-knob switch to correspond to the printhead being used complicates the manufacturing process of the printing device.

[Purpose of the invention]

In view of the above conventional problems, an object of the present invention is to provide a printing device that can automatically set a sequence process corresponding to the print head to be used without using a dedicated ROM or adjusting a depth switch. shall be.

[Key points of the invention]

In order to achieve the above object, the present invention provides a print head including an optical writing element array consisting of a number of optical writing elements according to the printing resolution and printing width, and an output light emitted from the print head according to printing information. In a printing device comprising an image forming process section including a photoreceptor that receives light,
a determining means for determining the number of optical writing elements of the print head; a selection setting means for selecting and setting reference time data for sequence control according to the number of optical writing elements determined by the determining means; and setting by the selection setting means. and control means for performing sequence control in accordance with the reference time data obtained.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

This embodiment describes an example of an LED printer as a printing device, and FIG. 2 is an overall configuration diagram of the LED printer. In the figure, an LED printer 1 includes a process section 4 consisting of a photosensitive drum 2, a print head 3, etc., a paper transport mechanism 7 consisting of a paper feed cassette 5, a paper feed roller 6, etc., an interface controller board 8, and a printer controller board. It is composed of a control circuit section 10 consisting of Fi9.

A process section 4 includes a photosensitive drum 2 that is rotatable in the direction of arrow a.
The photosensitive drum 2 includes a charger 11, a print head 3, a developer 12, a transfer device 13, and a cleaner 14, which are sequentially arranged near the circumferential surface of the photoreceptor drum 2.

The paper transport mechanism 7 includes a paper feed cassette 5 that stores a predetermined amount of paper P, a paper feed roller 6 that transports the paper P from the paper feed cassette 5, a slip roll 15 for transporting the paper P, a paper discharge roll 16, It is composed of a resist plate 18 and the like. Also,
The fixing roll 17 transports the paper P and fixes the toner image transferred by the transfer device 13 on the paper P as will be described later.

On the other hand, the interface controller board 8 converts the character code output from the external host computer into dot pattern data, and stores this data in the memory.
, an interface controller circuit is provided which outputs data to the printer controller board 9 by exchanging signals with the printer controller board 9, which will be described later.

The printer controller board 9 controls the output of the dot pattern data output from the interface controller board 8 to the print head 3, and also controls the photosensitive drum 2, paper feed roller 6, slide roll 15, fixing roll 17, etc. A printer controller circuit is provided that outputs a control signal for rotation control based on the rotational speed and a temperature control signal to the fixing roll 17.

FIG. 1 is a circuit diagram of the interface controller circuit and head controller circuit. However, LED elements 3a, 3b, . . . in the print head 3 are also shown. In addition, the interface controller circuit 8
Although the specific circuit configuration of ' is not shown, the dot pattern data (DATA) written in a memory (not shown) is output to the printer controller circuit 9', and at the same time it is created inside the interface controller circuit 8'. A clock signal (CLK) is output to the head controller circuit 9'. The printer controller circuit 9' includes a microprocessor unit (hereinafter referred to as MPU) 20, a shift register 21, a latch circuit 22, an AND gate 23, and a driver circuit 24. Also driver circuit 2
4 are connected to corresponding LED light emitting elements 3a, 3b, . . . arranged in a line within the print head 3 described above.

Regarding the number of LED light emitting elements 3a, 3b, . . . , four types shown in Table 1 below are mainly used depending on the type of print head 3.

Here, for example, the LED light emitting elements 3a, 3b... are 24
For the type with 32 pieces, the resolution is 240DP
I (dots per inch) and is used in the print head 3 when printing on paper of maximum B4 size. In other words, for a head with a resolution of 240DPI, 111II
Requires a print density of 9.45 dots per II, B4
Since the paper width of the size paper is 257 mm, 24
29 LED light emitting elements 3a, 3b... are required, and due to the necessity of transmitting print data, 29 LED light emitting elements 3a, 3b, etc. are required as described above.
It is composed of 432 LED light emitting elements 3a, 3b... Similarly, the type B print head shown in the table has a resolution of 300 DPI and has 2560 LED light emitting elements 3a, 3 that can print on up to A4 size paper.
The type C print head has a resolution of 400 DPI and is composed of 3456 LED light emitting elements 3a, 3b, which can print on up to A4 size paper. The print head is a type D print head with a resolution of 400 DPI and 4096 LEDs that can print on up to B4 size paper.
This is a print head composed of light emitting elements 3a, 3b, . . . .

In addition, in this embodiment, the paper conveyance speed is 6011III1
/S, and the rotational speed of the photoreceptor drum 2 must also match this transport speed, and the resolution is
It must be the same not only in the direction in which the light emitting elements 3a, 3b, . . . For this reason, in the case of a type print head, in order to print at a resolution of 240 DPI, 1
It must be scanned at a speed that prints 567 lines per second, so the scanning time for one line is 1.764 m5
(11567s). Similarly to the above calculations for type B to D print heads, the scanning time for type B print head is 1.411 m5, and the scanning time for type C and type D print heads is 1.411 m5. is 1.058m5.

The shift register 21 includes the LED light emitting elements 3a and 3b.
It has an area for holding the same data as the number of data points arranged therein, and inputs the dot pattern data outputted from the above-mentioned interface controller circuit 8' in synchronization with a clock signal. Further, as will be described in detail later, the shift register 21 inputs black print data or white print data output from the MPU 20 in synchronization with the same clock signal (MCLK) output from the MPU 20. When black print data or white print data exceeding the area to be input is input, the black print data etc. input first from the shift register 21 is output to the MPU 20 (Dtn).

The latch circuit 22 latches the print data in the shift register 21 in synchronization with the latch signal output from the MPU 20. In addition, the print data latched by the latch circuit 22 is processed by the strobe signal (STR) output from the MPU 20.
) is output to the corresponding driver circuit 24 via the AND gate 23. The driver circuit 24 is configured to control the lighting of the corresponding LED light emitting elements 3a, 3b, . . . according to input print data.

Further, from the MPU 20 to the interface controller circuit 8', a vertical synchronization signal (VSYNC) for setting the scanning time for sheets of paper, a horizontal synchronization signal (H3YNC) for setting the line scanning time for the LCD light emitting element, and a printer controller circuit 9 ' outputs a status signal (STATUS) containing various data. Furthermore, a status signal ((, -3TATUS) indicating each state of the interface controller circuit 8' is outputted from the interface controller 8' to the MPU 20.

Next, the print control operation of the LED printer 1 will be explained, focusing on the initial setting operation of the LED printer 1 having the above configuration. First, when the main power of the LED printer 1 is turned on, initial setting processing of the LED printer 1 is performed under the control of the interface controller circuit 8' and the printer controller circuit 9'.

This initial setting processing includes pre-rotation processing of the photoreceptor drum 2,
These processes include heating the fixing roll 17, setting a sequence for the print head 3 to be used, and detecting the size of the paper to be used. Here, the paper size detection process is performed by the MPU 2 by a paper detection mechanism (not shown) provided in the paper feed cassette 5.
0 controls detection.

Further, the sequence setting process for the print head 3 to be used is performed according to the flowchart shown in FIG.

That is, the MPU 20 first reads the black print data MDATA.
(For example, data “1”) is output to the Nantes gate 26.However, what is output to the Nantes gate 26 is MDATA.
Therefore, data "0" is actually output), and at the same time, a clock signal (MCLK) is output to the Nantes gate 27,
A counter (not shown) is counted up (steps (hereinafter referred to as S in FIG. 3) 1, S2). After that, M.P.
U 20 c't clock signal (V to LK) output and M
The count-up process of a counter (not shown) in the PU 20 is repeated, and the shift register 21 receives a clock signal (M
CLK), the print data input via the Nantes gate 26 is sequentially transferred, and when further print data is input after the print data has been input to all areas of the shift register 21, the first input black print data is Input from the shift register 21 to the MPU 20 (Din). for example,
If the print head 3 of this embodiment uses the print head of type A in Table 1 described above, the LED light emitting elements 3a, 3b
... consists of 2432 pieces of print data, and when the 2433 pieces of print data are output to the shift register 21, the black print data input to the shift register 21 first is sent to the MPU 20.
(33 is Y). Therefore, when black print data is input to the MPU 20, the MPU 20 sets the data to be output to the Nantes gate 26 to °°1°', and the attached print head 3 is set based on the count value counted by the counter at this time. It can be determined that the print head 3 is of type A. Thereafter, the MPU 20 sets a sequence corresponding to type A (S4).

On the other hand, when black print data is first input from the shift register 21 to the MPU 20, the count value of the counter is '256.
1", the MPU 20 similarly determines that a type B print head 3 is installed and performs the corresponding sequence settings thereafter. Also, if a type C or D print head 3 is installed, Also, when black print data is input to each MPU 20, the count value of the counter is “34”.
57' or 4097''', the MPU 20 can easily determine that the corresponding type C or type D print head 3 is attached, and can subsequently set the corresponding sequence.

The sequence settings include the output time of the horizontal synchronization signal, the setting time of the jam timer, etc. based on the determined type of print head 3, and the output time of the vertical synchronization signal based on the paper size detection described above.

After executing the above initial setting process, the LED printer 1 executes normal printing process (S5). That is, as described above, the character code output from the host computer is converted into dot pattern data by the interface controller circuit 8', and after one page of paper is stored in a memory (not shown), it is detected by the paper detection process described above. A time vertical synchronization signal corresponding to the paper size is output to the interface controller circuit 8'. Further, a time horizontal synchronization signal corresponding to the aforementioned sequence setting is output to the interface controller circuit 8', and while the horizontal synchronization signal is being output, the print data stored in the memory is supplied to the shift register 21.

The output duration of the horizontal synchronizing signal, which is the time during which this print data is output to the shift register 21, corresponds to the area capacity of the shift register 21, that is, the number of LED light emitting elements 3a, 3b, etc., as described above. It is. The print data input to the shift register 21 in this way is latched in the latch circuit 22 in synchronization with the latch signal, and then sent to the corresponding LED light emitting elements 3a, 3b, . . . via the driver circuit 24 in synchronization with the strobe signal. By supplying the light to the LED light emitting elements 3a, 3b, etc., the lighting can be controlled. As described above, the LED light emitting elements 3a, 3b.
The light emitted from .

Next, FIG. 4 is a circuit diagram of an LED printer according to a second embodiment of the present invention, which has basically the same circuit configuration as that shown in FIG. The difference is that the output of is connected to a relay 28, a resistor R, and an analog-to-digital conversion circuit (hereinafter referred to as an A/D conversion circuit) 29. With this circuit configuration, the relay 2 is turned off during initial setting, and the MPU 20 outputs 4096 pieces of black print data, which is the maximum among the data shown in Table 1, to the shift register 21 via the Nantes gate 26. After that, the MPU 20 outputs a strobe signal to light up all the LED light emitting elements 3a.
, 3b, . . . and outputs corresponding digital data to the MPU 20 based on the current value input to the A/D conversion circuit 29. MPU20 uses LED from input digital data.
The number of light emitting elements 3a, 3b, . . . to be provided is determined. For example, in the case of a type A print head 3 in which 2432 LED light emitting elements 3a, 3b, etc. are arranged, digital data corresponding to the amount of current flowing through the 2432 LED light emitting elements is input, and the MPU 20 easily It can be determined that the type A print head 3 is attached.

Therefore, similarly, even if type B, C, or D print heads 3 are installed, it can be determined from the digital data input to the MPU 20, and based on this determination, the output time of the horizontal synchronization signal is set, and from then on, the above-mentioned first Print processing can be executed in the same way as the processing shown in the figure.

Next, FIG. 5 is a circuit diagram of an LED printer according to a third embodiment of the present invention, which is basically the same as the circuit configuration shown in FIG. 30 to the LED light emitting elements 3a, 3b..., and
D The DC value of the current flowing through the light emitting elements 3a, 3b...
The /D conversion circuit 29 outputs the data to the MPU 30 as digital data. Even with this configuration, the MPU
20 can easily determine the type of print head 3 attached.

As described in detail above, in this embodiment, at the time of initial setting, the output time of the horizontal synchronization signal is determined depending on the number of LED light emitting elements 3a, 3b, etc. disposed in the print head 3, and the output of the vertical synchronization signal is determined depending on the paper size. The MPU 20 determines the data necessary for sequence control to set the time, and thereafter automatically performs the printing process corresponding to the attached print head 3.
This is executed by the ED printer 1.

Note that the embodiment of the present invention is not limited to the above example. For example, as shown in FIG. The configuration may also be such that the signal is supplied to the /D conversion circuit 29. Further, although the present invention has been described using an example of an LED printer as a printing device, it is of course applicable to other printing devices such as an LCD printer.

[Effects of the Invention] As described above in detail, according to the present invention, data on the element arrangement density and paper size of the print head attached to the printing device are determined in advance in the printing device during initial settings, and Dedicated ROM to execute appropriate sequence control
There is no need to use or adjust depth switches.

Therefore, it is possible to prevent an increase in the cost of the device and improve the manufacturing efficiency of the device.

[Brief explanation of drawings]

Figure 1 is a circuit configuration diagram of an LED printer according to an embodiment, Figure 2 is a circuit diagram of an LED printer according to an embodiment.
3 is a flowchart explaining the initial setting operation of the LED printer according to the embodiment; FIG. 4 is a circuit diagram of the LED printer according to the second embodiment; FIG. 5 is a circuit configuration diagram of an LED printer according to a third embodiment, and FIG. 6 is a circuit diagram of an LED printer showing a modification of the above embodiment. 1... LED printer, 2... Photosensitive drum, 3... Print head, 3a. 4 ・ ・ 5 ・ ・ 7 ・ ・ 8 ・ ・ 8′ ・ 9 ・ ・ 9′ ・ 17 ・ ・ 20 ・ ・ 21 ・ ・ 22 ・ ・ 24 ・ ・ 3b...LED light emitting element, ・Process section, ・Supply Paper cassette, ・Paper transport mechanism, ・Interface controller board, ・Interface controller circuit, ・Printer controller board, ・Printer controller circuit, ・Fuser roll, ・MPU.・Shift register, ・Latch circuit, ・Driver circuit.

Claims (1)

[Claims] An image forming process that includes a print head including an optical writing element array consisting of a number of optical writing elements according to the printing resolution and printing width, and a photoreceptor that receives light emitted from the print head in accordance with printing information. A printing device comprising: a determining means for determining the number of optical writing elements of the print head; and a selection setting means for selecting and setting reference time data for sequence control according to the number of optical writing elements determined by the determining means. and a control means for performing sequence control according to the reference time data set by the selection setting means.